Direct injection, spark ignition internal combustion engine

ABSTRACT

In a direct injection internal combustion engine with a combustion chamber which is delimited in each cylinder by a longitudinally movable piston and by the inner wall of a cylinder head, an injector injects fuel into the combustion chamber in order to form an ignitable fuel/air mixture with combustion air that is supplied separately, the mixture being ignited by a spark plug. The fuel is injected in a conical shape and the electrodes are protected from being wetted by fuel and from coking if they are located outside the lateral surface of the cone of fuel produced by the injection nozzle. In order to bring an ignitable mixture between the electrodes and to ensure an optimal operating performance of the internal combustion engine by improving the combustion process, the combustion chamber is configured so that the cone of fuel is injected in a free jet that is substantially unaffected by the perimeter of the combustion chamber, and the electrodes of the spark plug project inside a fuel vortex which emerges from the lateral surface during injection.

FIELD OF THE INVENTION

The present invention relates to a direct injection gasoline engine,

BACKGROUND INFORMATION

In direct injection gasoline engines, a combustion chamber is delimitedin each cylinder by a longitudinally movable piston and by the innerwall of a cylinder head, an injector injecting fuel into the combustionchamber in order internally to form a fuel/air mixture with combustionair that is supplied separately. The composition of the fuel/air mixturemust be within the ignitable window in the area of the spark plug inorder to be ignitable by an ignition spark, which is triggered betweenthe electrodes of a spark plug.

U.S. Pat. No. 5,577,473 describes an injection nozzle for directintroduction of fuel or fuel-air mixture in a combustion chamber of aninternal combustion engine. The injection nozzle includes a valve needlewhich opens to the outside, and between its valve head and a cone-shapedvalve seat an umbrella-like injection jet is formed from fuel orfuel-air mixture, the lateral surface of which points toward the sparkplug. The quantity of fuel that is introduced is metered so that theinternal combustion engine is operated with a lean fuel-air mixture, theair/fuel ratio (lambda) of which is on average >1, a ring-shaped guidesurface area being provided next to the valve seat in the outletdirection of the injection jet, which has a recess that deviates fromthe ring shape in an area that is oriented towards the spark plug.

European Published Patent Application No. 0 835 994 describes a directinjection internal combustion engine, which includes a shed roof-shapedcombustion chamber and an injector arranged in the center, theelectrodes of the spark plug being arranged near the intake valve. Thefuel is injected in the form of a hollow cone into a piston, whichincludes a cavity with a circular-shaped projecting part, and the fuelimpinges on the piston recess. The fuel which thus becomes sprayed istransported by a tumble flow to the electrodes of the spark plug, thecircular-shaped projecting part of the piston recess preventing thesprayed fuel from being scattered in the direction of the cylinder wall,whereby a stable stratified charge combustion is ensured.

German Published Patent Application No. 195 46 945 describes a directinjection internal combustion engine, the injectors of which inject thefuel into the combustion chamber in a cone shape via their injectionnozzles, the spark plug being arranged in such a way that its electrodesare outside of the lateral surface of the fuel cone generated by theinjection nozzle. This arrangement prevents wetting of the electrodeswith fuel during the injection operation and counteracts soot depositionon the electrodes because of incompletely burned fuel. The electrodesare free of coking over a long operating time period, whereby an orderlyoperation of the internal combustion engine without misfiring should beensured. In order to bring the ignitable mixture between the electrodesarranged outside of the fuel cone, the spark plug is to be arranged insuch a way that the ground electrode is at a small distance from thelateral surface of the fuel cone and the inner wall of the cylinder headextends parallel to the lateral surface of the fuel cone while forming agap at least where the electrodes of the spark plug are arranged.

In the gap, a turbulent flow should be produced, which is composed of afuel/air mixture and which extends into the area of the electrodes. Inorder to generate the turbulent flow, a special shape of the inner walland an arrangement of the spark plug near the injector is necessary. Theinjector is arranged in a recess of the inner wall, i.e., set back fromthe free combustion chamber volume, whereby the mixture vortex isproduced in the area adjacent to the injection nozzle and shouldcirculate in the hollow space that is formed between the lateral surfaceof the fuel cone and the inner wall of the cylinder head in the area ofthe injection nozzle. Furthermore, air, which was displaced by the fuelthat was injected into the combustion chamber, should flow back throughthe air gap between the fuel cone and the parallel, likewise cone-shapedinner wall of the cylinder head. During the return flow to the sparkplug along the inner wall, additional small portions of the fuel shouldalso be entrained from the fuel cone. The turbulent flow is formed sothat it is sufficiently pronounced in the area near the injector, inorder to bring an ignitable mixture between the electrodes of a sparkplug. The spark plug must therefore be arranged near the injector.

In the conventional direct injection gasoline engines, the combustionchamber perimeter must be precisely designed at a high expense,especially through the inner wall of the cylinder head, in order toobtain the desired hydromechanical effects to form the ignitable mixturevortex. The conventional combustion chamber configuration with thecombustion chamber shape necessary to form the mixture vortex and thespark plug necessarily arranged near the injector often cannot achieveoptimum combustion or ensure the desired operating performance of theinternal combustion engine.

It is an object of the present invention to provide a direct injectiongasoline engine so that the internal combustion engine operates withoptimum operating performance.

SUMMARY

In the combustion chamber configuration according to the presentinvention, the fuel cone is injected in a free jet that is substantiallyunaffected by the combustion chamber perimeter, i.e., the fuel cone isinjected at a sufficiently large distance, in particular, from the innerwall of the cylinder head, that the cone-shaped fuel jet spreads out inthe free combustion chamber volume substantially without hydromechanicalwall effects of the combustion chamber perimeter. In the process,vortices of fuel emerging from the lateral surface of the cone formduring the injection. These vortices are composed at first mainly offuel vapor and mix with the surrounding combustion air in the combustionchamber. The fuel vortices form in a particularly pronounced manner ifthe cone angle of the fuel jet cone is between 70° and 110° and they aregenerated by an air flow that occurs in the area of the lateral surfaceof the fuel cone because of air entrained by the fuel jet, while an airflow is also generated in the opposite direction by the resultingvacuum. The spark plug is positioned according to the present inventionso that the electrodes project into the fuel vortex of the free jet. Forexample, the spark position of the electrodes is 1 mm to 15 mm away fromthe lateral surface of the fuel cone.

The fuel vortex, which brings an ignitable mixture between theelectrodes, forms on the lateral surface of the free jet withouteffective influence of the combustion chamber perimeter, so that thecombustion chamber shape may be configured freely. A jet-guidedcombustion process is present in which wall effects of the inner wall ofthe cylinder head or possibly a piston cavity barely exert an influenceon the mixture formation or the ignition. In particular, in thestratified charge operation of an internal combustion engine, when fuelis injected during the compression stroke and a central fuel cloud isformed when the combustion chamber is filled with air, an optimalburn-through of the combustion chamber charge may be achieved with asimple combustion chamber configuration. Another advantage of themixture formation according to the present invention is that the sparkplug may be arranged further away from the injector. The fuel vortexremains stable for a long time almost at the same position in thecombustion chamber, so that ignition may occur independently of theinjection point over a wide time interval.

The free fuel jet is injected, for example, into the combustion chamberin a hollow cone shape. In this manner, the fuel vortices form in ashape that is particularly suitable for the transport of the mixture tothe spark plug, in particular, for injection at a high cylinder pressurein the compression phase during the stratified charging operation. Inorder to form the hollow cone jet, an injector with an injection nozzlethat opens to the outside may be used. The injection nozzle may in thiscase be constructed so that the fuel emerges from the injector asperpendicularly as possible to the surface of the opening valve element,so as to counteract depositions and coking. Injection nozzles with swirlgenerators may be used or even injectors with two magnetic coils formoving the valve element opening to the outside. Also, injection nozzlesthat open to the inside, i.e., into the inner space of the injector maybe provided, which generate a distinctive hollow cone jet. In thismanner, a higher fuel concentration is produced on the edge of the jetwith more than ⅔ of the entire injected amount in the outer third of thefuel cone. In order to form the hollow cone jet, injectors withmulti-hole nozzles may also be used, the fuel openings of the multi-holenozzle being arranged so that a hollow cone jet is formed from theindividual jets passing through during fuel injection. Fundamentally,any injector that generates a distinctive hollow cone jet with itsconstructive design may be suitable for the fuel injection in a free jetaccording to the present invention.

In order to form a distinctive fuel vortex on the injection cone, theinjector is arranged so that an angle between an axis of symmetry of thefuel cone and a cylinder axis of the cylinder is less than 25°. Theinjection nozzle may be at a distance of less than 20 mm away from thecylinder axis. The injector may be arranged centrally in the combustionchamber, the axis of symmetry of the injected fuel cone coinciding withthe axis of the cylinder.

In another example embodiment of the present invention, two spark plugsare provided per cylinder. Through a double ignition, in which bothspark plugs form ignition sparks, the risk of misfiring may be reduced.Also, under extreme operating conditions of the internal combustionengine, if possibly the fuel vortex transports too lean a mixturebetween the electrodes of a spark plug, ignition may still be ensuredthrough the other spark plug. The two spark plugs may be arranged atequal distance from the injector in the combustion chamber. If the sparkplugs with their respective ignition positions are located at differentdistances from the injector, then depending on the operating point ofthe internal combustion engine, the spark plug that is used for ignitionmay be the one more favorably positioned with regard to the formation ofthe fuel vortex. The position of the fuel vortex is affected by thecounterpressure in the combustion chamber, so that the optimum sparkposition for ignition is variable in the characteristics map of theinternal combustion engine depending on the operating conditions of theinternal combustion engine, such as the injection time. In this manner,the ignition of the fuel vortex may be ensured in any case by one of theigniting spark plugs having different spark positions relative to thefuel cone.

A control unit may be provided which determines, as a function of theoperating conditions, which of the two spark plugs is used to ignite thefuel/air mixture. In the process, depending on the operating mode(stratified charge or homogeneous mixture formation) and the operatingconditions, the ignition at the most favorable ignition location isensured, where the fuel vortices emerging from the fuel cone cover thecorresponding spark plug.

The mixture formation in the combustion chamber may be improved bysuitable steering of the inflowing combustion air. For example, thecombustion air may be brought into the combustion chamber in a tumblemotion, where the combustion air rotates in an approximately circularmovement in a plane of the cylinder axis. Effective ignition is ensuredin the process through the spark plug, which is arranged in a rearsection of the flow path of the combustion air in the combustionchamber. In the case of a tumble flow with combustion air inflowing atfirst approximately parallel to the combustion chamber roof, the sparkplug may be arranged in the area of the air admission, i.e., adjacent tothe intake valve, for example, between two intake valves in multi-valveengines. In the case of reverse tumble flow, the spark plug may becorrespondingly arranged on the outlet side. Furthermore, the mixtureformation of the gasoline engine according to the present invention,with fuel injection in a free jet, may be improved through aswirl-shaped charging movement in the combustion chamber. With aswirling flow of the combustion air around the cylinder axis,asymmetries and skeins of the injected fuel jet may be reduced duringthe mixture formation and thus the ignition conditions may be improvedin the area of the vortices that emerge on the fuel cone. The swirl maybe generated by appropriately shaped intake channels, so-called swirl orspiral channels, through the offset of the intake valves or the rotatedradial valve cluster or, in multi-valve engines, by switching off thevalve or via adjustable throttle elements in the intake section.

The optimal cone angle of the fuel cone in the angle range between 70°and 110° for the formation of powerful fuel vortices in the jet edgearea is dependent on the combustion chamber shape, in particular, on thesetting angle of the valve axes of the gas exchange valves. In the caseof a combustion chamber roof angle of 180°, the optimal jet angle of thefuel cone is approximately 90°. The cone angle of the fuel cone may bereduced by approximately 1° to 2° when the roof angle decreases byapproximately 10°. Good mixture configurations are achieved in anacceptance range of approximately 20° above and below the theoreticallyoptimum cone angle of the cone jet, i.e., in the angular range ofapproximately 70° to 110°.

Ignition may occur after the end of the injection operationapproximately 0.1 ms to 1.5 ms after the end of injection.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal cross-sectional view through an internalcombustion engine.

FIG. 2 is an enlarged view of an end section of the valve needle of aninjector.

FIG. 3 is a schematic view of a position of the fuel in the combustionchamber after injection.

FIG. 4 is a cross-sectional view through a gasoline engine having doubleignition.

DETAILED DESCRIPTION

FIG. 1 illustrates a direct injection gasoline engine 1, in the cylinder2 of which a piston 3 is arranged so that it is longitudinally movableand delimits a combustion chamber 4 with inner wall 15 of a cylinderhead 5 set on cylinder 2. In cylinder head 5, a fuel injector 6 isarranged, which, arranged centrally on cylinder center axis 14 and aimedat piston 3, injects fuel directly into combustion chamber 4. Combustionair 16 required for the inner mixture formation is supplied through anintake channel 13 to combustion chamber 4. In cylinder head 5, anadditional spark plug 7 is arranged, the electrodes 12 of which projectinto combustion chamber 4, an ignition spark being triggered between theelectrodes 12 at the ignition time and penetrates combustion chamber 4during the sparkover of the ignitable mixture.

Injector 6 includes an injection nozzle 11 that opens to the outside,which generates a fuel jet that expands toward the piston and has ahollow cone shape. Electrodes 12 of spark plug 7 are outside of lateralsurface 9 of fuel cone 8 generated by injection nozzle 11 and thus arenot wetted by fuel during injection.

The injector is actuated piezoelectrically, the injection nozzle 11being opened and closed quickly and in a precisely adjustable manner bya piezo element. The formation of the desired free jet shape of the fuelcone results from suitable selection of the injection time and itsprecise observance during the operating cycle via the piezoelectricactuation of the injector.

The internal combustion engine operates in wide characteristics mapranges in stratified charge operation, the fuel being injected duringthe compression stroke of cylinder 2. Because of the late fuel injectionduring the operating cycle, a stratified combustion chamber chargingoccurs at locally different fuel concentrations, a very lean mixtureformed and/or pure air being located outside of the fuel cone 8.

In order to bring an ignitable mixture between electrodes 12 of sparkplug 7, the internal combustion engine includes a combustion chamberconfiguration of the type in which fuel cone 8 is injected in a free jetthat is substantially unaffected by the combustion chamber perimeter bycylinder head inner wall 15. Lateral surface 9 of fuel cone 8 may be faraway from inner wall 15, fuel vortices 10, which extend out of lateralsurface 9, forming on the free jet that is unaffected by the wall effectof the combustion chamber perimeter. Cone angle α of fuel cone 8 isbetween 70° and 110°, fuel vortices 10 on the cone edge being producedin an particularly pronounced manner. Optimum cone angle a of fuel angle8 is affected by the configuration of the combustion chamber, forexample, by the contour of the cylinder head inner wall or also theorientation of the outlet and intake channels and the gas exchangevalves, i.e., the flow direction of the combustion air in combustionchamber 4. For a flat inner wall having an angle of inclination of 0°,the optimal cone angle α is approximately 90°, with sufficientlypowerful fuel vortices 10 being formed on the cone edge in an angularrange of approximately 20° above and below the optimum cone angle α.With increasing slope of the combustion chamber perimeter throughcylinder head inner wall 15, optimum cone angle α is reduced byapproximately 1° to 2° for an approximately 10° increase in the innerwall inclination.

Fuel vortices 10 result because of an air flow in the area of lateralsurface 9 of the fuel cone through air that is entrained with the fueljet, an air flow in the opposite direction is also generated by thevacuum that is formed. Fuel vortices 10 transport fuel into combustionchamber areas that are far outside fuel cone 8, and they mix there withcombustion air 16, which flows in a tumble flow into combustion chamber4 in the direction of the arrow. In tumble flow, the combustion chambercharge moves in a plane that includes cylinder axis 14.

The spark plug is arranged so that electrodes 12 project into mixturevortex 10. Also, in the combustion chamber area positioned outside fuelcone 8, in which electrodes 12 are located protected from direct wettingby fuel, an ignitable mixture may be provided on spark plug 7 with fuelvortices 10 that are present during the free jet injection.

Fuel vortices 10 form substantially independently of the combustionchamber shape, and inner wall 15 of cylinder head 5 may thus beconfigured in any desired manner. The injection free jet has a hollowcone shape, a high portion of the entire fuel injection quantity beingconducted in lateral surface 9 of cone jet 8 and may thus be covered byfuel vortices 10.

The ignition time can be varied and adjusted as necessary in a widerange substantially independently of the injection time, since the fuelvortices become pronounced in a stable manner over a longer time periodand fuel is still present on spark plug 7 at approximately 50°crankshaft angle after the end of injection.

Because of the stability of fuel vortices 10 and the long time periodthat is available for ignition, spark plug 7 may be arranged relativelyfar away from injector 6 in the cylinder head, whereby the combustionchamber configuration and the constructive arrangement of the cylinderhead 5 are considerably simplified. The distance of the spark positioncorresponding to the arrangement of electrodes 12 from the injectionnozzle may be between 7 mm and 30 mm. The spark position is thus between1 mm and 15 mm away from lateral surface 9 of fuel cone 8. The distanceof electrodes 12 from fuel cone 8 is selected according to the desiredoperating performance in the respective application case of the directinjection gasoline engine 1.

FIG. 2 illustrates an enlargement of the end section of injector 6 thatis projecting into the combustion chamber. A longitudinally movablevalve needle 21 is arranged in injector 6, which forms the sealingmember of injector 6 that opens to the outside, i.e., into thecombustion chamber. The tip of valve needle 21 and the valve seat ofinjector 6 are configured so that the fuel jet to be injected emergesfrom injector 6 at an angle α, which is in a range of between 70° and110°. The fuel jet may emerge perpendicularly to the surfaces of outsideedges 23 of valve needle 21, whereby a reduced sensitivity of the valveneedle results relative to deposits or the coking. Angle of emergence αthus determines the cone angle of the hollow cone jet that is generatedby injector 6.

FIG. 3 schematically illustrates a combustion chamber 4, in which thefuel is concentrated in a toroid shape through the vortex that emergesout of the lateral surface of the fuel jet that is injected. Fuel toroid22 moves during the mixture formation in the inner space 4 according tothe flow direction of the inflowing combustion air. Tumble flow orreverse tumble flow may be advantageous, where a charging movementoccurs in the direction of the arrow.

FIG. 4 illustrates a n example embodiment of gasoline engine 1 accordingto the present invention with two spark plugs 7, 7′ per cylinder 2. Forsimplicity, the reference indicators from FIG. 1 are provided forequivalent structural components.

Injector 6 is arranged in a central position in the combustion chamberon cylinder axis 14 and injects a hollow cone shaped fuel jet 8 intocombustion chamber 4. The two spark plugs 7, 7′ are arrangedasymmetrically to cylinder axis 14 at different distances from injector6 in cylinder head 5. The spark positions correspond to the respectivepositions of electrodes 12 of spark plugs 7, 7′ and are different forthe two spark plugs relative to fuel cone 8. In the characteristics mapof internal combustion engine 1, different injection times may beadvantageous for different load ranges in regard to the operatingbehavior of internal combustion engine 1. In the process, fuel vorticesemerge from cone lateral surface 8 at different points depending on theoperating mode (stratified charge operation/homogenous mixtureformation) and the operating conditions of the internal combustionengine. Spark plugs 7, 7′ are arranged according to the lateral surfacezone, in which fuel vortices may occur over the entire stratifiedloading characteristics map of the internal combustion engine, with eachof spark plugs 7, 7′ being adjacent to the extreme positions of the fuelvortices in the possible cone lateral surface. In this manner, it isensured that at each operating point with stratified charging of theinternal combustion engine and under all possible operating conditions,the emerging fuel vortex may be ignited by at least one of the twoavailable spark plugs 7, 7′.

Electrodes 12 of each of the spark plugs 7, 7′ are outside of hollowcone jet 8 and are thus protected from being directly wetted by fuel. Acontrol unit 17 may determine, as a function of the provided operatingmode of internal combustion engine 1 and the measured values of theoperating conditions of the internal combustion engine (e.g., rpm,load), which of the two spark plugs 7, 7′ is used to ignite the fuel/airmixture in combustion chamber 4. The corresponding data for ignitioncontrol may be made available in a characteristics map memory of controlunit 17, to be extracted as needed. Control unit 17 coordinates theignition, i.e., the selection of spark plugs 7, 7′ and the ignition timewith the injection parameters, and controls injector 6. Ignition mayoccur after the end of the injection operation, for example, in a timeperiod of between 0.1 ms and 1.5 ms after the end of the injection.

Under extreme operating conditions of the internal combustion engine,both spark plugs 7, 7′ may be used in the same operating cycle of piston3 and to ensure reliable mixture ignition via double ignition atdifferent spark positions.

Piston 3 includes, in its piston head 18, a piston cavity 19 whichsupports, by a turbine blade-type contour, the formation of the fuelvortices that emerge out of fuel jet 8 and contributes, particularly inthe stratified charge operation, to the stabilization of thetoroid-shaped mixture cloud. Piston cavity 19 includes a centralelevation 20 which extends approximately at the level of the axis ofsymmetry of hollow cone jet 8, i.e., it is located in a central positionin piston head 18 in the combustion chamber configuration. The centralelevation is surrounded by a bulb-type recess, a blade-type contourbeing formed for the impinging fuel jet.

What is claimed is:
 1. A direct injection gasoline engine, comprising: acombustion chamber delimited in each cylinder by a longitudinallymovable piston and an inner wall of a cylinder head; an injector havingan injection nozzle configured to inject fuel into the combustionchamber in a cone-shaped manner to form an ignitable fuel/air mixturewith separately supplied combustion air; and a spark plug havingelectrodes arranged outside a lateral surface of the cone of fuelinjected by the injection nozzle and located in an area of andprotruding into a mixture vortex; wherein the injection nozzle isconfigured to inject fuel in a hollow, cone-shaped free jetsubstantially unaffected by a combustion chamber boundary; wherein acone angle of the fuel cone is between 70° and 110°; and wherein theinjector includes an injection nozzle opening to an outside so that fuelvortices are formed substantially independently of the combustionchamber shape, emerge from the lateral surface of the injected fuel andare concentrated in the combustion chamber in a torus shape.
 2. Thedirect injection gasoline engine according to claim 1, wherein theinjector includes a multi-hole nozzle, the nozzle holes of themulti-hole nozzle being arranged to produce a hollow cone jet fromindividual jets emerging during fuel injection.
 3. The direct injectiongasoline engine according to claim 1, wherein the injector is arrangedso that an angle between an axis of symmetry of the fuel cone and acylinder axis of the cylinder is less than 25°.
 4. The direct injectiongasoline engine according to claim 3, wherein the injection nozzle isdisposed at a distance of less than 20 mm from the cylinder axis.
 5. Thedirect injection gasoline engine according to claim 1, wherein theinjector is configured to be actuated piezoelectrically.
 6. The directinjection gasoline engine according to claim 1, wherein a spark positionof the electrodes is 1 mm to 15 mm from the lateral surface of the fuelcone.
 7. The direct injection gasoline engine according to claim 6,wherein the spark position of the electrodes is 7 mm to 30 mm from theinjection nozzle.
 8. The direct injection gasoline engine according toclaim 1, wherein the combustion chamber is configured to deflect inflowof combustion air in the combustion chamber to form a tumble flow in aplane that includes a cylinder axis, the spark plug being arranged in arear section of a flow path of the combustion air in the combustionchamber.
 9. The direct injection gasoline engine according to claim 1,wherein a piston head of the piston includes a piston recess having ablade contour with a projection arranged approximately at a height of acenter of the fuel cone.
 10. The direct injection gasoline engineaccording to claim 1, wherein the direct injection gasoline engine isconfigured to operate in wide characteristics map ranges with stratifiedcharging and fuel injection during a compression stroke.
 11. A directinjection gasoline engine, comprising: a combustion chamber delimited ineach cylinder by a longitudinally movable piston and an inner wall of acylinder head; an injector having an injection nozzle configured toinject fuel into the combustion chamber in a cone-shaped manner to forman ignitable fuel/air mixture with separately supplied combustion air;and a spark plug having electrodes arranged outside a lateral surface ofthe cone of fuel injected by the injection nozzle and located in an areaof and protruding into a mixture vortex; wherein the injection nozzle isconfigured to inject fuel in a hollow, cone-shaped free jetsubstantially unaffected by a combustion chamber boundary; wherein acone angle of the fuel cone is between 70° and 110°; wherein theinjector includes an injection nozzle opening to an outside so that fuelvortices are formed substantially independently of the combustionchamber shape, emerge from the lateral surface of the injected fuel andare concentrated in the combustion chamber in a torus shape; wherein aspark position of the electrodes is 1 mm to 15 mm from the lateralsurface of the fuel cone; wherein the spark position of the electrodesis 7 mm to 30 mm from the injection nozzle; and wherein the directinjection gasoline engine includes two spark plugs per cylinder.
 12. Thedirect injection gasoline engine according to claim 11, wherein thespark position of each spark plug is the same distance from theinjector.
 13. The direct injection gasoline engine according to claim11, wherein the spark position of each spark plug is at a differentdistance from the injector.
 14. The direct injection gasoline engineaccording to claim 11, wherein the spark plugs are configured fordual-firing ignition.
 15. The direct injection gasoline engine accordingto claim 11, further comprising: a control unit configured to determinewhich of the two spark plugs is used to ignite a fuel/air mixture. 16.The direct injection gasoline engine according to claim 15, wherein thecontrol unit is configured to determine which of the two spark plugs isused to ignite the fuel/air mixture based on a operating mode of thedirect injection gasoline engine.
 17. The direct injection gasolineengine according to claim 15, wherein the control unit is configured todetermine which of the two spark plugs is used to ignite the fuel/airmixture based on operating conditions of the direct injection gasolineengine.
 18. The direct injection gasoline engine according to claim 17,wherein the operating conditions include an rpm.
 19. The directinjection gasoline engine according to claim 17, wherein the operatingconditions include a load.
 20. The direct injection gasoline engineaccording to claim 15, wherein the ignition is configured to occur afteran end of the injection operation.
 21. The direct injection gasolineengine according to claim 15, wherein the ignition is configured tooccur in a time period of between 0.1 ms and 1.5 ms after an of theinjection operation.